Hadza agree: do more and live longer

Can the Hadza, a group of hunters and gatherers, help us understand how to maintain cardiovascular health? A recent study claims that the answer is yes, in two ways. First, we can correlate their health to their levels of activity. Second, we can extrapolate from these present-day hunters and gatherers to the thousands of generations in which the common ancestors of all humans lived similarly. That is, we can say that humanity evolved to thrive under certain levels of activity.

In this study, led by David Raichlen of the University of Arizona’s School of Anthropology, researchers deployed activity monitors and collected fluids from a subset of the Hadza people in Tanzania. They worked with individuals who continued to exclusively engage in hunting and gathering. They then compared various measures of activity and energy expenditure to earlier measures of cardiovascular health among Hadza, although these included individuals who also pursued other economic strategies, such as working in tourism.

The researchers’ first claim is, by far, the strongest. Sadly, it’s the least remarkable. Hadza hunters and gatherers undertook much more “moderate-to-vigorous physical activity” than the U.S. government currently recommends. (The amount depends on the type of measurement used.) And Hadza people have relatively high levels of cardiovascular health into old age. Thus, this research adds another indication that greater activity results in a healthier heart. If the study had included the effects of diet, the claim would be even stronger.

As for their second claim, Raichlen and his collaborators argue that the Hadza stand in for the common ancestors of all humanity, who also were hunters and gatherers for millions of years until the development and spread of agriculture about ten thousand years ago. Thus, they reason, our physiology has evolved to support the same levels of activity as the Hadza still undertake.

I’m hardly the first to point out that this is a questionable contention. The social and environmental circumstances in which today’s Hadza hunt and gather are quite distinct from those of the past. And it’s possible that our common ancestors lived under various conditions requiring more or less activity of different kinds. No one actually knows.

So, rather than a window to the past, this article provides another perspective on the present. The upshot: do more! Then you’ll stay alive to do it longer.

2 responses to “Hadza agree: do more and live longer”

Interesting post. If it’s questionable whether our physiology has evolved to support the same levels of activity as the Hadza still undertake, what about the idea that our physiology has evolved to support the same diet as the Hadza and other hunter-gatherers, which is the logic behind the current oh-so-trendy paleo diet?

Right – if the Hadza jumped off a bridge, should we follow? I say this: subgroups of humans have evolved to handle different diets since the development of agriculture (e.g. lactose tolerance), so the ‘best’ diet is a moving target. And it’s not guaranteed that our ancestors maximized their nutrition. Plus we don’t really know the details of the diets of our various pre-agricultural ancestors, including the extent of cooking. So why not look for correlations among the diets, activity levels, and health of living humans, of which there are many?